Inception also understands "Big Oh" ideas -- when you are looping inside the third level down, you have 10 seconds on the outside giving you 10^3 seconds on the inside. (EDIT: a single "tick" in one level allows for 20 or so "ticks" at the next level of dreaming, because of extra brain capacity during sleep.) Hehe -- I loved the movie...
Except the human brain doesn't have the capacity to process so fast that seconds turns into years. None the less, the movie was entertaining and I'm just gonna leave it there. I know movie logic shouldn't be a comparison to real world logic, but the geek in me can't help but point out illogical happenings in the film.
Hence you see your dream to shift from one place, to the other. Here is a very good NOVA documentary on netflix about it: http://www.netflix.com/WiMovie/What_Are_Dreams_Nova/70129639...